LTSA with microstrip-slotline transition for MFPA imaging systems

The arranging density of the feeding antenna is the main factor which decides the spatial sampling rate of the millimeter-wave focal plane array(MFPA) imaging systems. This paper proposes a new kind of feed antenna. Comparing with the other feeding antennas, it has broader waveband, lower side lobe, lower mutual coupling, a moderate gain and constant input impedance in a very wide frequency range. It is easier to form a close feed array which can realize an effective exposure to the lens or the reflector antenna with less over flow loss. A detailed theoretical analysis, simulation and optimization of the design are done to develop the linearly tapered slot antenna(LTSA), its microstrip-slotline transition and antenna feed array. They show the good availablity of LTSA in MFPA imaging systems.